Human beings, like all things, have a nature. When human beings do not meet your expectations, there may be many reasons. One of those reasons is that your expectations may be contrary to human nature. There is an all too common tendency, especially in our time, to talk about how people should be, rather than recognize how they are. Imagine that you plan a picnic, but it rains. It would be a waste of time to gripe that it should be a sunny day. The only real choice is to make alternate plans. Likewise, human beings universally have traits that occasionally disappoint others, especially those others who believe that human nature does not acually exist, that it is merely a social convention. But it does exist, and it is not always what you like. Nothing you can do about that. So you have to judge humanity in total, and not just based on the fact that humans occasionally are disappointing or bewildering. In general, human beings are heroic creatures, doing a pretty decent job of surviving as a species, and accomodating their social milieu. Being selfish, often to the exclusion of others interests, is part of the nature of man. It is healthier to recognize it, and work around it, rather than imagine it will change for your sake or that it somehow should be different.